ISSN: 2319-5967
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International Journal of Engineering Science and Innovative Technology (IJESIT)
Volume 3, Issue 5, September 2014
A comparative study of meiotic chromosomes
from three different species of short horned
grasshopper
Tarali Kalita and Karabi Dutta
Abstract: The shorthorned grasshopper is an insect that belongs to family acrididae and order orthoptera. The
grasshopper fauna is although very rich in North- East India, in comparison to other parts of the world including India,
the cytological knowledge on different species of grasshopper is very limited. Therefore, an attempt has been made to
study the chromosome pattern of three different species of shorthorned grasshopper found in Assam viz. Altractomorpa
crenulata, Hieroglyphus banian, Oxya multidentata. The present paper represents an account of chromosome number,
structure and behaviour during meiosis of male individual of three species of shorthorned grasshopper which may help to
analyse the basis diversification among the three species.
Key words: Shorthorned grasshopper; Chromosome; Meiosis
I. INTRODUCTION
The grasshopper is an insect of the suborder caelifera in the order orthoptera. The shorthorned grasshopper
belongs to family acrididae as their antennae are shorter than the body. Grasshopper have worldwide
distribution and found in open grassland and abundant leafy vegetation. Recent estimate indicates some 2,400
valid caelifera genera and about 11,000 valid species of grasshopper described to date (8). In India the
grasshopper fauna represents 102 species (45% of world’s population) (2). North-East India situated between 220
and 29028’N latitude and between 89045’ and 97023’ E longitude has produced a good number of grasshopper
species but to date the actual number is not estimated.
The chromosomes are the most significant component of the cell and are the carrier of genetic specification
from one generation to the next. Besides, they play an important role in variation, mutation, evolution, control of
morphogenesis, multiplication and equilibrium of vital process. Orthopteran species has been considered as a
classical material for karyological investigations. The size and number of their chromosomes are such that both
quantitative and qualitative studies on chromosomal anomalies can be detected easily (11). Grasshopper of order
orthoptera, are of immense economic importance as on one hand they are used as food in many countries of the
world and on the other hand they are the biggest destroyer of the standing crops all over the world. To know
such an economically important insect in detail it is better to understand the cytogenetic pattern. Although
grasshopper holds extreme clarity in their divisional stages, such type of cytological investigation is very limited
on the grasshopper species found in north eastern India. Therefore, an attempt has been made to study the
chromosome pattern of three different species of short horned grasshopper found in Assam.
The present paper incorporates an account of chromosome number, structure and behaviour during meiosis in
male individuals of three species of short horned grasshopper available in Assam.
II. MATERIALS AND METHODS
The specimen were collected from three different places of the state namely Pathsala, Rani and Tihu during the
month of May to August’ 2012 and 2013 and identified as Altractomorpa crenulata, Hieroglyphus banian and
Oxya multidentata following Uvarov’s classification (12).The insects were dissected in insect saline (0.42%
potassium chloride) and testes of each individual were then fixed in freshly prepared 1:3 mixture of glacial
acetic acid and methanol of Sanfelic fixative (4).The chromosome slides were prepared following squashing
method and stained in the 2% acetic orcein stain (10) .Photographs were taken with the help of Sony digital still
camera and Leica bright field microscope with photographic attachment. Statistical data analysis was performed
using one way and two ways ANOVA in PASW statistics 18.
III. RESULTS
The observations were made from the squash preparation of testes follicles of three species of short horned
grasshopper and recoded as follows------
176
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Species1: Altractomorpa crenulata (Fig 1A)
Spermatogonial metaphase plates showed the presence of twenty three number chromosomes (Fig.1F). The sex
chromosome (X) was positively hetropycnotic upto diplotene stage. In leptotene the chromosomes appear as a
mass of single threads (Fig 1 D) while in zygotene the homologus chromosomes have paired (Fig1E).
Centromeric division is distinct in late metaphase II and early Anaphse II (Fig 1F) and the chromatids move to
the respective poles. The chromosomes appeared as rod shaped without much banding in metaphaseII and some
have ring like structure. Measurement made of chromosomes from metaphase plate showed the presence of four
long, five medium and three short chromosome. A study of chiasma frequency revealed that the loss of chiasma
was stronger between diplotene and diakinesis.
Species2: Hieroglyphus banian (Fig 1B)
The diploid chromosome number as revealed from the study of spermatogonial plates was twenty three
(22A+X). At the zygotene stage, the faintly stained chromosome threads are found jumbled and haphazard (Fig1
G).The autosomal bivalents and the deeply stained X could be seen at the diplotene stage but at diakinesis stage
the bivalents assumed the normal appearance. Larger bivalents were usually with two chiasmata and the
maximum number of chiasmata observed in a bivalent was four (Fig 1 H). The metaphase II chromosomes (Fig
1 I) appeared as rod shaped or ring shaped and they could be classified into five long including X chromosome,
four medium and three short chromosomes.
Species3: Oxya multidentata (Fig 1C)
The diploid chromosome number is found 2n=23 including X chromosome. At laptotene stage the autosomes
faintly stained along with the spherical shape darkly stained mass of X chromosome (Fig 1 J). All the bivalents
in the late diplotene have more than one chiasma (Fig 1K). At metaphase all the chromosomes become oval,
ring, elongated and v-shaped. The chromosome could be classified into five large, four medium and three short
chromosomes. The chiasma frequency study revealed that the loss of chiasma was frequent between diplotene
and diakinesis.
Statistical data analysis using one way ANOVA with the data of mean length of chromosomes in the three
species of grasshopper showed that the difference in chromosome length of the three species is significant
(p=0.662>0.05). On the other hand, two way ANOVA performed with data of chaisma frequency in different
stages of meiosis in the three studied species was found to be non significant (p=0.019<0.05) regarding the
difference in chaisma frequency.
IV. DISCUSSION
The diploid chromosome number in all the three species of short horned grasshopper under the present
investigation was found to be twenty three (22A+X) . The entire short horned grasshopper except those under
group Chasmosacci show this characteristic chromosome number (1, 3, 6). The chromosome behaviour during the
spermatocyte division was orthodox in all the three species and was in no way different from other species of
grasshopper with twenty three chromosomes. As earlier findings the sexual system was represented by a XO in
males (13). The X chromosome was outstandingly larger and darkly stained from the same stain applied to
autosomes in all the three species. At leptotene the sex element appears as a hetropyncotic mass lying very often
close to nuclear membrane which is the characteristic features of sex chromosome of short horned
grasshopper(7). At zygotene along with the increase in the volume of nucleus, the sex chromosome also increases
in size into an irregular vesicular mass. At pachytene this irregular shape of the sex chromosome is gradually
eliminated and in some nuclei it appears as a deeply stained rod-like structure. At metaphase I the sex
chromosome usually does not show any staining difference but at times it may appear to be slightly negatively
heteropycnotic in comparison to bivalents. However, its identification at this stage is not difficult since it
generally forms an accessory plate lying sometimes near one of the poles of the spindle. At metaphase II the sex
chromosome looks identical with the autosomes. Only a comparative metrical study would reveal its existence
and size.
The autosomal lengths were found to be variable in the nuclei of the same gonad cells. The maximum length
observed for an individual autosome was 7.07 um and the minimum length was 1.41 um. Majority of the
autosomes in a nucleus were generally in between 3 and 6 um in length. Altractomorpa crenulata have medium
sized chromosome while Hieroglyphus banian and Oxya multidentata have longer and shorter chromosome
177
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respectively. Chiasma frequency was found to be more in Hieroglyphus banian as compared to Altractomorpa
crenulata and Oxya multidentata. In longer chromosomes the number of chiasma becomes more (9). Increased
chiasma frequency increases the rate of diversification which is very much important from taxonomic point of
view.
From the above finding it is not possible to draw a concrete conclusion to analyse the basis of diversification
among the three species. Therefore, further cytological investigation of the three species of short horned is
required to subscribe clues to the definite systematic differences, if any.
REFERENCES
[1] Asana J. J. “Studies on the chromosome of Indian Orthoptera VI. The idiochromosomes of Hierodula sp.” Curr. Sci .
vol. 2, pp 244-245, 1934.
[2] Channaveerappa H. and Ranganath H. A. “Karyology of a few species of south Indian acridids” J. Biosci. Vol.22 (3),
pp 367–374, 1996.
[3] Chadha P. and Mehta A. “Chromosome complement and c-banding pattern in six species of grasshopper”.
International Journal of Genetics and Molecular Biology. Vol. 3(1), pp 25-30, 2011.
[4] Darlington C. D. and La Cour L. F. “The handing of chromosomes”. George Allen and Unwin Ltd. 1966.
[5] Dutta M. K. “A Cytological investigation on the genus Phloeba (Acrididae)”. Proc. Nat. Inst. Sci. India. Vol.14, pp 1314, 1948.
[6] Manna G. K. “A study of chromosomes during meiosis in fifteen species of Indian grasshopper. Proc. Zool. Soc. vol.
7,pp 39-58, 1954.
[7] Manna G. K. and Chatterjee K. “Polymorphic sex chromosome in Euprepocnemis sp. The meiosis in the XO type male
and in neo-X and neo-Y type male”. The Nucleus. vol. 6(2),pp 121-134, 1963.
[8] Mason G. “Chromosomal differentiation through an Alpine hybrid zone in grasshopper Chorthippus parallelus.”
Evolutionary Biology. vol. 12 (3), pp 577-585, 1999.
[9] Phukan A. “Studies on the chromosome morphology and estimation of the chiasma frequency and crossing over during
spermatogenesis of Oxya multidentata”, Ph.D Thesis Gauhati University, 1970.
[10] Sarma A. K. and Sharma A. “Chromosome Techniques”, Butterworth’s, London, 3rd edition: pp 9-27, 1980.
[11] Turkoglu S. and Koca S. “Karyotype, C- and G-band Patterns and DNA content of Callimenus (=Bradyporus)
macrogaster macrogaster”. J. of Insect Sc. vol. 2, pp 24, 2002.
[12] Uvarov B. “Grassohoppers and locusts; a handbook of general acridology”. Cambridge University Press, pp. 344–351.
1966.
[13] White M. J. D. “The evolution of the sex chromosome, the X chromosome in the Tettigonidae and Acrididae and the
principle of evolutionary isolation of the X”. J. Genet. Vol. 42, pp 173-190, 1941.
178
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APPENDIX
Table 1: Mean length and percentage length of the second meiotic division metaphase chromosome in three species of
short horned grasshopper
CHROMOSOME NUMBERS
1
2
3
4
5.43
4.50
3.30
3.05
in
SPECIES
A.crenulata
Mean
length
micra
Percentag
e length
Mean
length in
micra
Percentag
e length
Mean
length in
micra
Percentag
e length
H. banion
O. multidentata
5
2.93
6
2.75
7
2.60
8
2.30
9
2.12
10
1.57
11
1.41
X
3.64
15.24
12.63
9.35
8.56
8.22
7.72
7.29
6.46
5.95
4.41
3.96
10.23
7.07
5.55
4.64
4.08
3.25
3.09
2.56
2.56
2.01
1.74
1.47
3.89
16.87
13.24
11.07
9.74
7.75
7.38
6.11
6.11
4.79
4.15
3.50
9.28
5.23
4.38
3.85
3.61
3.09
3.00
2.89
2.66
2.42
2.14
1.66
4.09
13.40
11.22
9.61
9.25
7.91
7.68
7.40
6.81
6.22
5.48
4.27
10.50
Table 2: Chiasma frequency at different stages of meiosis in three different species of short horned grasshopper
Species
Stages
meiosis
A.crenulata
H. banion
O. multidentata
of
NO. Of nuclei
Total chiasma
Total
chiasma
Diplotene
10
180
67
18.0
Diakinesis
10
146
83
14.6
MetaphaseI
10
142
122
14.2
Diplotene
10
176
34
17.6
Diakinesis
10
151
51
15.1
MetaphaseI
10
143
86
14.3
Diplotene
10
141
29
14.1
Diakinesis
10
135
33
13.5
MetaphaseI
10
124
35
12.4
A
B
179
terminal
C
Chiasma
frequency
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D
F
E
I
G
H
J
K
L
Fig1: A-C photographs of studied species (A= Altractomorpa crenulata,B= Hieroglyphus banian,C= Oxya multidentata
), D-F Stages of meiosis in Altractomorpa crenulata (D= leptotene with spherical X chromosome,E=Zygotene, F=
Centromere division in anaphase II ), G-I Stages of meiosis in Hieroglyphus banian (G=zygotene,H=diplotene,
I=metaphase II), J-L Stages of meiosis in Oxya multidentata (J=Faintly stained chromosome threads and deeply
stained X chromosome at leptotene stage, K= Bivalents with two/three chiasmata at diakinesis stage L= metaphase
II)
180